Study on the diffusion law of variable pressure gradient grouting in sandy dolomite
In order to study the influence of dolomite sandification on tunnel grouting reinforcement in the construction section of Yuxi construction section of Yunzhong Water Diversion Project,then reveal the law of slurry diffusion,a series of in-depth studies of scanning electron microscopy(SEM)experiments,theoretical analysis and multiphysics fluid-structure interaction numerical analysis were carried out.The results show that,dolomite sanded under dissolution and developed internal structure with multi-scale pore-fracture network distribution characteristics,during grouting injection,the slurry has a front surface during diffusion migration and produces obvious fingering phenomenon,fractures with different developmental configurations can lead to irregularity and instability of the diffusion morphology of cement slurry.Compared to traditional constant pressure grouting,variable pressure gradient grouting is more conducive to uniform filling of multi-scale fractures developed by complex strata after sanding,after the slurry solidifies,the cemented and broken rock mass reduces the stress distribution area of the surrounding rock,and alleviates the stress concentration phenomenon of the vault and arch bottom,it has a more significant effect on improving the stability of surrounding rock.The above studies can provide a theoretical reference for the actual grouting engineering design and construction of sanded dolomite strata tunnels.
rock mechanicssanded dolomitewater diversion in Central Yunnangrouting diffusionvariable pressure gradientfluid-structure coupling
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